This section provides background information related to the present disclosure and which is not necessarily prior art.
Transfer cases are used in all-wheel drive vehicles for the distribution of the torque to a plurality of axles. The distribution takes place by a multi-disk clutch which is made such that the torque transmission between a first output shaft and a second output shaft can be controlled. On engagement by means of a controllable multi-disk clutch, one speaks of “torque on demand”.
The lubrication of transfer cases whose multi-disk clutch above all has a high cooling oil requirement in slip operation usually requires a separate oil supply. In addition, in particular on a blocking of the multi-disk clutch, the bearings which support the components of the multi-disk clutch are fully loaded, with the friction between the bearings and the components being at a maximum.
EP 0 268 904 B1 describes a transfer case having a transmission with a pump-less oil lubrication of a planetary gearset, wherein gears act as an oil pump to build up a specific pressure and wherein the lubrication oil is supplied to the planetary gearset through a passage and a gap between concentric shafts. The passage is integrated in the transmission housing. The transmission of EP 0 268 904 B1 thus does not have any direct oil lubrication of the multi-disk clutch and requires a complex and/or expensive housing design to form the passage.